I have a new (to me) Nordic Tug 26 with an 85 hp Perkins. The winterizing checklist from the PO is:

I empty the fresh water tanks which should also drain the hot water tank.
empty the black water tank and add some RV antifreeze to the black water tank through the toilet(head)
drain and clean the raw water strainer
Run the engine and that will pump the water out of the exhaust system
optional -is to fill the fuel tank to lessen the amount of condensation. That fuel adds a lot of weight to pull around.
check the amount of coolant in the radiator-top off.
put some RV . antifreeze in the sink traps

Though this is a mighty simple boat compared to most, this seems a little “light”. I’ll be storing on a trailer in very cold E-WA.

Take it from someone who's boat has to endure -10F temps for days or even a week at a time - if I miss something I will be replacing it in the spring.

Running the engine will never pump all the water out of the system. The only way to be sure the raw water system of the engine is safe is either to drain EVERY piece of the raw water system or run enough RV antifreeze through it to ensure that only pure RV antifreeze remains.

Drain the water tanks, drain the HW tank.
Bypass the HW tank and disconnect the water hose at the main water tank, draw in RV antifreeze through the entire system - going to each faucet - hot and cold, shower hose - everything - running each one until only pure RV antifreeze comes out. If you have sink traps then indeed they should also get a good dose of RV antifreeze.

Disconnect the input line from the head and draw in RV antifreeze until you're certain the head and any valves downstream have only pure RV antifreeze in them.

If the black water tank is empty then nothing else needs to be done to it.

Another thing - when done, leave valves open. If a valve is closed and has water inside it - that valve will crack. Yeah, most seacocks can be drained when they're closed, but on the hard its easier to just leave them open. But this also goes for water faucets and shower valves, too.

Greetings,
Mr.h. I would make doubly sure that the water heater is in fact completely drained as a result of draining the fresh water tanks. Either blow the residual water out of the lines and leave your taps open or blow out and fill the lines with RV anti-freeze. Bypass the water heater, as any RV anti-freeze is difficult to remove from the water heater in the spring.

I would NOT run the engine dry, on the hard, to attempt to eliminate any water in the exhaust system. RV anti-freeze poured or sucked into the sea strainer while the engine is running and RV anti-freeze shows strongly in the exhaust water.

Yes, all good advise above. I use -100 antifreeze and test each outlet with a refractometer to see what the antifreeze is actually good to. Simply seeing the antifreeze come out isn’t necessarily a positive indication that you have good coverage. My first year winterizing my present boat the antifreeze came out of the exhaust but when we tested it it showed +20 degrees. It took twice as much to actually get it to -20 degrees. We have a funnel made for winterizing that bungees into the intake strainers that has a hose built into it for sucking the antifreeze into the engines, works extremely well. I end up using about 40 gallons of -100 to do my whole baot. 2 diesel engines, diesel generator, 2 A/C units, 2 heads, all the water system, 2 bilge pumps, seawater washdown system and a shower sump.

Yes, all good advise above. I use -100 antifreeze and test each outlet with a refractometer to see what the antifreeze is actually good to. Simply seeing the antifreeze come out isn’t necessarily a positive indication that you have good coverage. My first year winterizing my present boat the antifreeze came out of the exhaust but when we tested it it showed +20 degrees. It took twice as much to actually get it to -20 degrees. We have a funnel made for winterizing that bungees into the intake strainers that has a hose built into it for sucking the antifreeze into the engines, works extremely well. I end up using about 40 gallons of -100 to do my whole baot. 2 diesel engines, diesel generator, 2 A/C units, 2 heads, all the water system, 2 bilge pumps, seawater washdown system and a shower sump.

Nice! At 40 gallons you even have me beat and I thought I used a lot. But rather safe than sorry on this one - antifreeze is cheap compared to boat parts!

For the engines, I drain my sea strainers and heat exchangers first, then disconnect the outlet hose from the sea strainer to the engine and attach to a 5 gal bucket - then start engine to suck it through - I use 5 gallons for each main engine and 3 for the gen. At that point I have very little water to displace so it comes out almost pure for a while before I shut down.

Thank you all. I have it pretty complete list now. My systems are fairly simple. Raw water and fresh water systems, sinks. The hot water heater has been drained and there is a bypass system in place. I just thought to drain the raw water washdown as well.

I found a Groco raw water strainer adapter that looks like it’ll work well for running antifreeze through the system.

Assume at some time there could be a power outage, remote as that may seem, so depending upon heaters to maintain temp may be disastrous.

I agree with KCHASE. If not done properly you will be replacing/repairing it come spring.

Hot water tank: Do not assume the hot water tank will drain when you drain the water tanks. It likely will not so it needs to be actively drained. I get most of the water out including the use of a siphon into a bucket for that last inch or so and then it's ok as what water remains is so shallow even if it freezes it won't harm the tank. Lots of expansion room. You might use a small pump to do the same thing as the siphon. Do NOT pink A/F the tanks or you will have a devil of a time getting taste out.

I also A/F the fresh water pump. I made mine easily done by using garden hose fittings, GOOD ONES, and some auxiliary extension hoses for the purpose and simply use a large saucepan or bucket into which the A/F has been put and let 'er run. Just needs a few seconds. Recommissioning in spring is the reverse although with a bit more water.

The toilet, assuming manual: pull the intake hose off the seacock and then pump antifreeze into the toilet. Just filling the bowl and pumping will not take care of the pump itself. That will A/F only 1/2 of the pump. Once the toilet pump has been done then I add more to the toilet and pump that into the hldg. tank to A/F what ever water is left in the tank. THat will take care of the other 1/2 of the pump and the hoses. A hand pump just needs the lever set and it will empty the bowl without trying to pull any more water into itself. I also run the pump out pump just enough to flood it with A/F. THose pumps are expensive. Note, the holding tank has already been flushed so no 'stuff'..

[[Run the engine and that will pump the water out of the exhaust system]]

There will be water left in low lying parts, the raw water pump, the heat exchanger, and other areas that you may not be aware of. Just assuming the engine will dump whatever is in it is not enough and it likely will leave enough to damage something.. You need to figure a way to use the engine to pull pink A/f into the system displacing any raw water. I pull the hose off the seacock, put it into a nearly full 5 gal pail and start and then as the level drops I add more up to a total of 7 gal. I want enough through that it does not just lightly dilute the raw water but displaces almost all of it.. This also takes care of my strainer. Study the engine. You may do better to deal with a strainer separately and figure out another hose to feed the raw water pump but you will have to study it a bit.

Yes, check the engine A/F concentration and adjust if need be..

Check the sink drains. Most boats do not have traps like your house. They usually simply go overboard. No harm done if you do put some A/F through but it may be a waste.

As for filling the fuel tanks , lots of different opinions. I do but my boat winters in the water at the marina. Trailering is not an option.

I will suggest you check the filler caps. THere should be O ring seals on the caps or in the body where the cap contacts. The threads and O rings lightly greased to help seal and prevent the threads seizing.. If the O rings are in poor shape that may allow rain water to enter. Other wise replace the rings. They are so cheap it's not worth taking a chance. NOte the sizes in the log for the future.

Be prepared to ventilate the cabin also as moisture , thus mildew, can be a BIG problem. Read the threads about dehumidifiers. You don't have to have one but good venting is a must then. Those dehum. can do a good job and if the cabin is dry the mildew won't show.

If left out of the water the through hull valves should be left open but also exercized to the open position as some small amount of water may be trapped in the sides. THat lets them drain. Good seacocks may have drain plugs in the side.

Fresh water lines are drained, blown out if need be, but often a little study will show how gravity can be used drain them. Faucets are left open.

Any work should have a list of what was done because sure as heck you will forget something at commissioning time next spring which could be costly, dollars and time.

I just finished winterizing both my boats for winter here in Maine. This video shows the procedure for the water system and head on my powerboat. Winterizing the engine is very simple. I disconnect the intake hose on the strainer and replace it with a short section of heater hose and put the other end in a bucket of propylene glycol antifreeze (RV antifreeze) I then start the engine and let it run until I have put 4 gallons of antifreeze through. A larger engine might take a bit more, but certainly no more than 6 gallons. Winterizing the engine takes about 2-3 minutes. I agree that you should leave all the seacocks open.

One of the things I do to winterize the heads and sea water washdown in order to not have to disconnect the hoses at the through hull is take 1/2 of an outboard flush muff and put it up against the intake through hulls with a bucket of antifreeze hooked to the muff. Then go inside and pump the head and run the pump for the wash down. Someone has to hold the muff up to the intake, but it is much easier than unhooking the hoses.

I just finished winterizing both my boats for winter here in Maine. This video shows the procedure for the water system and head on my powerboat. Winterizing the engine is very simple. I disconnect the intake hose on the strainer and replace it with a short section of heater hose and put the other end in a bucket of propylene glycol antifreeze (RV antifreeze) I then start the engine and let it run until I have put 4 gallons of antifreeze through. A larger engine might take a bit more, but certainly no more than 6 gallons. Winterizing the engine takes about 2-3 minutes. I agree that you should leave all the seacocks open.

My engines each take 10 gallons of -100 to get -20 protection out of the exhausts. It will depend on how much water your engines and mufflers have in them. I test the output to get it to -20. 5 gallons will show the blue coming out of the exhaust but will be around +20 degrees which is not near enough.

One of the things I do to winterize the heads and sea water washdown in order to not have to disconnect the hoses at the through hull is take 1/2 of an outboard flush muff and put it up against the intake through hulls with a bucket of antifreeze hooked to the muff. Then go inside and pump the head and run the pump for the wash down. Someone has to hold the muff up to the intake, but it is much easier than unhooking the hoses.

Good idea - I have seen a similar hook up made from a rubber toilet plunger w short pipe inserted in place of the wooden handle, hole drilled through, valve & hose fitting, hose to container of AF. Our yard handles winterizing this way while it is in the lift - drum of AF mounted aboard the lift gravity flow to the thru hull.

Yes, I have a 5 gallon bucket that I put a hose bib at the bottom. I hang the bucket off the bow rail and hook a short garden hose from the bucket bib to the muff so it has a bit of head pressure and then run the head or wash down pump. Much easier than unhooking the hoses which are in awkward locations.

Lock-out the power to the hot water tank... it is WAY too easy to flick that breaker or switch back on while messing with other stuff...

Over the years, land, water, RV...I have been known to disconnect wires, pull the breaker right out of the panel, install switches at both the panel and locally at the water heater... I went thru replacing a blown element once, swore NEVER again...

I use a Seaflush adapter to flush the engines. Just use a paper towel to make a gasket on the strainer and bungee the flush adapter to the strainer. Use the large suction hose to suck the antifreeze into the engine from a 5 gallon bucket. I can winterize each engine in about 5 minutes without unhooking any hoses.